U.S. patent application number 15/494135 was filed with the patent office on 2017-11-02 for machining system.
This patent application is currently assigned to Fanuc Corporation. The applicant listed for this patent is Fanuc Corporation. Invention is credited to Keisuke KUNIHIRO.
Application Number | 20170312875 15/494135 |
Document ID | / |
Family ID | 60081511 |
Filed Date | 2017-11-02 |
United States Patent
Application |
20170312875 |
Kind Code |
A1 |
KUNIHIRO; Keisuke |
November 2, 2017 |
MACHINING SYSTEM
Abstract
A machining system includes a robot arm for changing a workpiece
or inspecting a machined workpiece, and a probe that is attached to
a distal end portion of the robot arm via a force sensor, where the
robot arm is controlled such that the probe is arranged at a
predetermined measurement position in contact with a side surface
of a tool holder, where detection values of the force sensor are
obtained over a predetermined period of time in a state where a
main spindle is performing rotation operation, where an attached
state of the tool holder is determined based on the detection
values obtained over the predetermined period of time.
Inventors: |
KUNIHIRO; Keisuke;
(Yamanashi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Fanuc Corporation |
Yamanashi |
|
JP |
|
|
Assignee: |
Fanuc Corporation
Yamanashi
JP
|
Family ID: |
60081511 |
Appl. No.: |
15/494135 |
Filed: |
April 21, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B25J 13/085 20130101;
B25J 15/0066 20130101; B23Q 7/043 20130101; Y02P 90/02 20151101;
Y02P 90/087 20151101; B25J 11/005 20130101; B23Q 17/22 20130101;
B23Q 2017/001 20130101 |
International
Class: |
B23Q 17/22 20060101
B23Q017/22; B23Q 7/04 20060101 B23Q007/04; B25J 11/00 20060101
B25J011/00; B25J 13/08 20060101 B25J013/08 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 28, 2016 |
JP |
2016091927 |
Claims
1. A machining system comprising: a machine tool for machining a
workpiece by rotating a tool attached to a main spindle; a robot
including at least one robot arm, for conducting a change of the
workpiece for the machine tool or an inspection of the workpiece
after machining; a contact section that is attached to a distal end
portion of the robot arm via a force sensor; and a control unit,
wherein the control unit is configured to conduct: a measurement
process of controlling the robot arm such that the contact section
is positioned at a predetermined measurement position where the
contact section comes into contact with a side surface of the tool
or a side surface of a tool holder for attaching the tool to the
main spindle, and obtaining detection values of the force sensor
over a predetermined period of time in a state where the main
spindle is rotating; and a determination process of determining an
attached state of the tool or the tool holder based on the
detection values obtained over the predetermined period of
time.
2. A machining system comprising: a machine tool for machining a
workpiece by rotating a tool attached to a main spindle; a robot
including at least one robot arm, for conducting a change of the
workpiece for the machine tool or an inspection of the workpiece
after machining; a displacement sensor that is attached to a distal
end portion of the robot arm; and a control unit, wherein the
control unit is configured to conduct: a measurement process of
controlling the robot arm such that the displacement sensor is
positioned at a predetermined measurement position where the
displacement sensor can detect displacement of a side surface of
the tool or a side surface of a tool holder for attaching the tool
to the main spindle, in a direction orthogonal to a center axis of
the main spindle, and obtaining detection values of the
displacement sensor over a predetermined period of time in a state
where the main spindle is rotating; and a determination process of
determining an attached state of the tool or the tool holder based
on the detection values obtained over the predetermined period of
time.
3. A machining system comprising: a machine tool for machining a
workpiece by rotating a tool attached to a main spindle; a robot
including at least one robot arm, for conducting a changed of the
workpiece for the machine tool or an inspection of the workpiece
after machining; a contact section that is attached to a distal end
portion of the robot arm via a force sensor; and a control unit,
wherein the control unit is configured to conduct: a measurement
process of controlling the robot arm such that the contact section
is positioned at predetermined measurement positions where the
contact section comes into contact with a first circumferential
position, a second circumferential position, and a third
circumferential position of a side surface of the tool or a side
surface of a tool holder for attaching the tool to the main spindle
in a state where the main spindle is not rotated, and obtaining
detection values of the force sensor at the situations where the
contact section comes into contact with the first, the second, and
the third circumferential positions, respectively; and a
determination process of determining an attached state of the tool
or the tool holder based on the detection values.
4. A machining system comprising: a machine tool for machining a
workpiece by rotating a tool attached to a main spindle; a robot
including at least one robot arm for conducting a change of the
workpiece for the machine tool or for an inspection of the
workpiece after machining; a displacement sensor that is attached
to a distal end portion of the robot arm; and a control unit,
wherein the control unit is configured to conduct: a measurement
process of controlling the robot arm such that the displacement
sensor is positioned at predetermined measurement positions where
the displacement sensor can detect displacement or positions of a
first circumferential position, a second circumferential position,
and a third circumferential position of a side surface of the tool
or a side surface of a tool holder for attaching the tool to the
main spindle in a state where the main spindle is not rotated, and
obtaining detection values detected by the displacement sensor with
respect to the first, the second, and the third circumferential
positions, and a determination process of determining an attached
state of the tool or the tool holder based on the detection values,
wherein the displacement sensor detects the displacement or the
positions of the first, the second, and the third circumferential
positions, respectively, in a direction orthogonal to a center axis
of the main spindle.
5. The machining system according to claim 1, further comprising a
measurement position information storage unit storing information
about each predetermined measurement position in association with
each of a plurality of types of tools, wherein the measurement
process includes referring to the information, and controlling the
robot arm such that the contact section or the displacement sensor
is positioned at each predetermined measurement position according
to the type of the tool.
6. The machining system according to claim 2, further comprising a
measurement position information storage unit storing information
about each predetermined measurement position in association with
each of a plurality of types of tools, wherein the measurement
process includes referring to the information, and controlling the
robot arm such that the contact section or the displacement sensor
is positioned at each predetermined measurement position according
to the type of the tool.
7. The machining system according to claim 3, further comprising a
measurement position information storage unit storing information
about each predetermined measurement position in association with
each of a plurality of types of tools, wherein the measurement
process includes referring to the information, and controlling the
robot arm such that the contact section or the displacement sensor
is positioned at each predetermined measurement position according
to the type of the tool.
8. The machining system according to claim 4, further comprising a
measurement position information storage unit storing information
about each predetermined measurement position in association with
each of a plurality of types of tools, wherein the measurement
process includes referring to the information, and controlling the
robot arm such that the contact section or the displacement sensor
is positioned at each predetermined measurement position according
to the type of the tool.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based on Japanese Patent Application No.
2016-091927 filed on Apr. 28, 2016, the content of which is
incorporated herein by reference.
TECHNICAL FIELD
[0002] The present invention relates to a machining system, and
more particularly, to a machining system including a machine tool,
and a robot for changing a workpiece at the machine tool or for
inspecting a machined workpiece.
BACKGROUND ART
[0003] As a machining system, a system which has, attached to a
contact surface to a tool holder at a lower end portion of a main
spindle of a machine tool, a plurality of strain gauges and an
output circuit for outputting detection results of the plurality of
strain gauges outside, and which detects presence/absence of chips
or foreign substances between the contact surface and the tool
holder based on output values of the output circuit is known (for
example, see PTL 1).
CITATION LIST
Patent Literature
[0004] {PTL 1} [0005] Japanese Unexamined Patent Application,
Publication No. 2000-79537
SUMMARY OF INVENTION
[0006] A machining system according to a first aspect of the
present invention includes a machine tool for machining a workpiece
by rotating a tool attached to a main spindle; a robot including at
least one robot arm, for conducting a change of the workpiece for
the machine tool or an inspection of the workpiece after machining;
a contact section that is attached to a distal end portion of the
robot arm via a force sensor; and a control unit, wherein the
control unit is configured to conduct: a measurement process of
controlling the robot arm such that the contact section is
positioned at a predetermined measurement position where the
contact section comes into contact with a side surface of the tool
or a side surface of a tool holder for attaching the tool to the
main spindle, and obtaining detection values of the force sensor
over a predetermined period of time in a state where the main
spindle is rotating; and a determination process of determining an
attached state of the tool or the tool holder based on the
detection values obtained over the predetermined period of
time.
[0007] According to the first aspect, when the side surface of the
tool or the side surface of the tool holder is displaced in a
direction orthogonal to a center axis of the main spindle while the
main spindle is rotating, the force acting on the force sensor is
changed according to the displacement. Accordingly, if the position
of the side surface of the tool or the side surface of the tool
holder is deflected in a direction orthogonal to the center axis of
the main spindle, the runout is reflected in the detection values
that are obtained over the predetermined period of time. That is,
the attached state of the tool or the tool holder can be determined
based on the detection values.
[0008] A machining system according to a second aspect of the
present invention includes a machine tool for machining a workpiece
by rotating a tool attached to a main spindle; a robot including at
least one robot arm, for conducting a change of the workpiece for
the machine tool or an inspection of the workpiece after machining;
a displacement sensor that is attached to a distal end portion of
the robot arm; and a control unit, wherein the control unit is
configured to conduct: a measurement process of controlling the
robot arm such that the displacement sensor is positioned at a
predetermined measurement position where the displacement sensor
can detect displacement of a side surface of the tool or a side
surface of a tool holder for attaching the tool to the main
spindle, in a direction orthogonal to a center axis of the main
spindle, and obtaining detection values of the displacement sensor
over a predetermined period of time in a state where the main
spindle is rotating; and a determination process of determining an
attached state of the tool or the tool holder based on the
detection values obtained over the predetermined period of
time.
[0009] According to the second aspect, when the side surface of the
tool or the side surface of the tool holder is displaced in a
direction orthogonal to the center axis of the main spindle while
the main spindle is rotating, detection values of the displacement
sensor change according to the displacement. Accordingly, if the
position of the side surface of the tool or the side surface of the
tool holder is deflected in a direction orthogonal to the center
axis of the main spindle, the runout is reflected in the detection
values that are obtained over the predetermined period of time.
That is, the attached state of the tool or the tool holder can be
determined based on the detection values.
[0010] A machining system according to a third aspect of the
present invention includes a machine tool for machining a workpiece
by rotating a tool attached to a main spindle; a robot including at
least one robot arm, for conducting a changed of the workpiece for
the machine tool or an inspection of the workpiece after machining;
a contact section that is attached to a distal end portion of the
robot arm via a force sensor; and a control unit, wherein the
control unit is configured to conduct: a measurement process of
controlling the robot arm such that the contact section is
positioned at predetermined measurement positions where the contact
section comes into contact with a first circumferential position, a
second circumferential position, and a third circumferential
position of a side surface of the tool or a side surface of a tool
holder for attaching the tool to the main spindle in a state where
the main spindle is not rotated, and obtaining detection values of
the force sensor at the situations where the contact section comes
into contact with the first, the second, and the third
circumferential positions, respectively; and a determination
process of determining an attached state of the tool or the tool
holder based on the detection values.
[0011] According to the third aspect, because the forces with which
the contact section comes into contact with the first, the second,
and the third circumferential positions are detected by the force
sensor in states where the contact section attached to the distal
end portion of the robot arm is positioned at the predetermined
measurement positions, if the side surface of the tool or the side
surface of the tool holder is shifted in a direction orthogonal to
a center axis of the main spindle, the detection values of the
force sensor change according to the shift. Accordingly, if the
position of a center axis of the tool or the tool holder is shifted
in the direction orthogonal to the center axis of the main spindle,
the shift is reflected in the detection values. That is, the
attached state of the tool or the tool holder can be determined
based on the detection values.
[0012] A machining system according to a fourth aspect of the
present invention includes a machine tool for machining a workpiece
by rotating a tool attached to a main spindle; a robot including at
least one robot arm for conducting a change of the workpiece for
the machine tool or for an inspection of the workpiece after
machining; a displacement sensor that is attached to a distal end
portion of the robot arm; and a control unit, wherein the control
unit is configured to conduct: a measurement process of controlling
the robot arm such that the displacement sensor is positioned at
predetermined measurement positions where the displacement sensor
can detect displacement or positions of a first circumferential
position, a second circumferential position, and a third
circumferential position of a side surface of the tool or a side
surface of a tool holder for attaching the tool to the main spindle
in a state where the main spindle is not rotated, and obtaining
detection values detected by the displacement sensor with respect
to the first, the second, and the third circumferential positions,
and a determination process of determining an attached state of the
tool or the tool holder based on the detection values, wherein the
displacement sensor detects the displacement or the positions of
the first, the second, and the third circumferential positions,
respectively, in a direction orthogonal to a center axis of the
main spindle.
[0013] According to the fourth aspect, because the displacement
sensor attached to the distal end portion of the robot arm detects
displacement or positions for the first, the second, and the third
circumferential positions, if the side surface of the tool or the
side surface of the tool holder is shifted in a direction
orthogonal to a center axis of the main spindle, the detection
values of the displacement sensor change according to the shift.
Accordingly, if the position of a center axis of the tool or the
tool holder is shifted in the direction orthogonal to the center
axis of the main spindle, the shift is reflected in the detection
values. That is, the attached state of the tool or the tool holder
can be determined based on the detection values.
[0014] Moreover, preferably, in each of the aspects described
above, a measurement position information storage unit storing
information about each predetermined measurement position in
association with each of a plurality of types of tools is further
included, where the control unit refers to the information, and
controls the robot arm such that the contact section or the
displacement sensor is positioned at each predetermined measurement
position according to the type of the tool.
[0015] According to this aspect, the contact section or the
displacement sensor is arranged at an appropriate position
according to the type of the tool, and thus, there is an advantage
when performing determination of an attached state after the tool
is changed.
Advantageous Effects of Invention
[0016] According to the present invention, an attached state of a
tool or a tool holder can be determined without adding equipment to
a main spindle.
BRIEF DESCRIPTION OF DRAWINGS
[0017] FIG. 1 is a schematic configuration diagram of a machining
system according to a first embodiment of the present
invention.
[0018] FIG. 2 is a schematic block diagram of the machining system
according to the first embodiment.
[0019] FIG. 3 is a flowchart showing example operation of a control
unit according to the first embodiment.
[0020] FIG. 4 is a flowchart showing example operation of a control
unit of a machining system according to a second embodiment of the
present invention.
[0021] FIG. 5 is an explanatory diagram of operation of the
machining system according to the second embodiment.
[0022] FIG. 6 is a flowchart showing example operation of a control
unit of a machining system according to a third embodiment of the
present invention.
[0023] FIG. 7 is an explanatory diagram of operation of the
machining system according to the third embodiment.
[0024] FIG. 8 is a flowchart showing example operation of a control
unit of a machining system according to a fourth embodiment of the
present invention.
[0025] FIG. 9 is an explanatory diagram of operation of the
machining system according to the fourth embodiment.
DESCRIPTION OF EMBODIMENTS
[0026] A machining system according to a first embodiment of the
present invention will be described below with reference to the
drawings.
[0027] As shown in FIG. 1, this machining system includes a machine
tool which machines a workpiece by a tool attached to a main
spindle 20 that is supported by a frame 10 and workpiece is
machined by rotating the main spindle 20. The main spindle 20 is
supported by the frame 10 via a main spindle support section 21,
and the main spindle 20 is moved in a vertical direction and is
rotated by a known structure of the machine tool. For example, the
main spindle 20 is rotated by a rotation servo motor 22 shown in
FIG. 2, and the main spindle 20 is moved in the vertical direction
by a vertical movement servo motor 23.
[0028] Furthermore, a workpiece holding section 11 where a
workpiece is placed and held and the main spindle 20 may be
configured to move relative to each other in a horizontal direction
by a known structure of the machine tool. For example, the
workpiece holding section 11 may be configured to move in a
horizontal X-axis direction by a servo motor and a linear screw,
and to move in a horizontal Y-axis direction by another servo motor
and another linear screw.
[0029] The machine tool has a tool 40, such as an endmill, a
milling cutter such as a face mill, a drill or the like, attached
to the main spindle 20 via a tool holder 30.
[0030] The machining system also includes a robot 50 having a robot
arm 60 for moving a workpiece before machining from a location
where the workpiece before machining is placed to the workpiece
holding section 11, and for moving a machined workpiece from the
workpiece holding section 11 to a location where a machined
workpiece is to be placed.
[0031] The robot 50 includes a base 51 that tilts with respect to
the horizontal direction (the left-right direction and the depth
direction in FIG. 1).
[0032] The robot arm 60 includes a base section 61 that is
supported by the base 51 in a manner capable of rotating around an
axis extending in a vertical direction, a proximal arm 62 that is
supported by the base section 61 in a manner capable of rotating
around an axis along a substantially horizontal direction, a middle
section 63 that is supported at a distal end of the proximal arm 62
in a manner capable of rotating around an axis along a
substantially horizontal direction, a distal arm 64 that is
supported by the middle section 63, and a chuck section 65 that is
supported at a distal end portion of the distal arm 64 in a manner
capable of rotating around an axis along a substantially horizontal
direction. The distal end of the distal arm 64 is configured to
rotate around its center axis.
[0033] Also, a sensor support section 70 is attached to the distal
end portion of the distal arm 64 of the robot arm 60. The sensor
support section 70 includes a base section 71 that is supported at
the distal end portion of the distal arm 64 in a manner capable of
rotating around an axis extending in a vertical direction, and an
arm 72 that is supported by the base section 71 in a manner capable
of rotating around an axis along a substantially horizontal
direction, and a force sensor unit 80 is supported at a distal end
portion of the arm 72 in a manner capable of rotating around an
axis along a substantially horizontal direction.
[0034] The force sensor unit 80 includes a force sensor 81 having a
known structure of a strain gauge type, a piezoelectric type or the
like, and a probe 82 as a contact section attached to a distal end
of the force sensor 81, and the force sensor 81 detects a force
acting on the probe 82 in the axial direction of the probe 82.
[0035] The robot 50 and the robot arm 60 include a servo motor 51a
for tilting the base 51, a servo motor 61a for rotating the base
section 61, a servo motor 62a for rotating the proximal arm 62, a
servo motor 63a for rotating the middle section 63, a servo motor
64a for rotating the distal end of the distal arm 64, a servo motor
65a for rotating the chuck section 65, and a servo motor 65b for
operating the chuck section 65.
[0036] The sensor support section 70 includes a servo motor 71a for
rotating the base section 71, and a servo motor 72a for rotating
the arm 72.
[0037] As shown in FIG. 2, each servo motor 51a, 61a, 62a, 63a,
64a, 65a, 65b of the robot 50, each servo motor 71a, 72a of the
sensor support section 70, and the rotation servo motor 22 and the
vertical movement servo motor 23 of the main spindle 20 are
connected to a control unit 90, and are controlled by the control
unit 90. The control unit 90 is also connected to the force sensor
81, and receives detection values of the force sensor 81.
[0038] The control unit 90 operates according to a workpiece change
program stored in a memory device 91 and controls each servo motor
51a, 61a, 62a, 63a, 64a, 65a, 65b to move, by the robot arm 60, a
workpiece before machining from a location where the workpiece
before machining is placed to the workpiece holding section 11 and
a machined workpiece from the workpiece holding section 11 to a
location where a machined workpiece is to be placed.
[0039] Furthermore, the control unit 90 operates according to an
attached state determination program stored in the memory device
91, and determines the attached states of the tool 40 and the tool
holder 30 attached to the main spindle 20. Example operation of the
control unit 90 at the time of determination of the attached state
of the tool holder 30 will be described with reference to the
flowchart shown in FIG. 3.
[0040] For example, when a predetermined timing comes and a
condition for determination start is satisfied, or when a condition
for determination start is satisfied by reception of a command for
attached state determination start input by a predetermined input
section by a worker (step S1-1), the control unit 90 controls each
servo motor 51a, 61a, 62a, 63a, 64a, 65a, 65b, 71a, 72a such that
the probe 82 is arranged at a predetermined measurement position in
contact with a side surface of the tool holder 30, as shown in FIG.
1, in a state where the rotation servo motor 22 and the vertical
movement servo motor 23 of the main spindle 20 are stopped (step
S1-2). At this time, the servo motors 71a, 72a are preferably
controlled such that the center axis of the probe 82 and the normal
line of the side surface of the tool holder 30 substantially
coincide with each other.
[0041] Next, the control unit 90 rotates the main spindle 20 by
controlling the rotation servo motor 22 (step S1-3), and causes the
memory device 91 to store detection values of the force sensor 81
over a predetermined period of time in a state where the main
spindle 20 is rotated (step S1-4).
[0042] The detection values to be stored may be a series of
detection values that are continuously detected during a
predetermined period of time (a series of detection values changing
according to rotation of the main spindle 20), or may be detection
values at a plurality of points obtained, at predetermined
intervals, from a series of detection values detected during the
predetermined period of time. Also, in the case where the control
unit 90 is configured to receive data regarding rotation positions
of the main spindle 20, the series of detection values or the
detection values at the plurality of points may be stored in the
memory device 91 in association with their rotation positions of
the main spindle 20.
[0043] Next, the control unit 90 determines the attached state of
the tool holder 30 based on the detection values obtained over the
predetermined period of time and stored in the memory device 91.
Specifically, for example, in the case where the difference between
the maximum value and the minimum value of the detection values
obtained over the predetermined period of time is smaller than a
predetermined reference value (step S1-5), the attached state is
determined to be normal (step S1-6), and in the case where the
difference between the maximum value and the minimum value of the
detection values obtained over the predetermined period of time is
equal to or greater than the predetermined reference value (step
S1-5), the attached state is determined to be abnormal (step S1-7),
and a display device 92 or a notification device 93 is controlled
to indicate that the attached state is abnormal (step S1-8).
[0044] In this manner, in the first embodiment, when the side
surface of the tool holder 30 is displaced in a direction
orthogonal to the center axis of the main spindle 20 during
rotation of the main spindle 20, the force acting on the force
sensor 81 is changed according to the displacement. Accordingly, if
the position of the side surface of the tool holder 30 is deflected
in a direction orthogonal to the center axis of the main spindle
20, the runout is reflected in the detection values obtained over
the predetermined period of time. That is, the attached state of
the tool holder 30 may be determined based on the detection
values.
[0045] Moreover, the attached state of the tool 40 may be
determined in the same manner if the probe 82 is made to contact
the side surface of the tool 40 in step S1-2.
[0046] A machining system according to a second embodiment of the
present invention will be described below with reference to the
drawings.
[0047] In contrast to the machining system of the first embodiment,
the machining system of the present embodiment includes a
non-contact or contact displacement sensor 83 at the distal end
portion of the arm 72 of the sensor support section 70, instead of
the force sensor 81 and the probe 82. Structures not described
below are the same as those in the first embodiment.
[0048] As the displacement sensor 83, a known non-contact
displacement meter, such as a laser displacement meter or an
ultrasonic displacement meter, or a contact displacement meter that
causes a probe to come into contact with a measurement target
object and that measures displacement or the position of the
measurement target object based on the amount of movement of the
probe may be used, for example.
[0049] Operation of the control unit 90 at the time of
determination of the attached state of the tool holder 30 according
to the present embodiment will be described with reference to the
flowchart in FIG. 4.
[0050] In the case where the displacement sensor 83 is of a
non-contact type, when a condition for determination start is
satisfied (step S2-1) as in the first embodiment, the control unit
90 controls each servo motor 51a, 61a, 62a, 63a, 64a, 65a, 65b,
71a, 72a such that the displacement sensor 83 is arranged at a
predetermined measurement position near the side surface of the
tool holder 30, as shown in FIG. 5, in a state where the rotation
servo motor 22 and the vertical movement servo motor 23 of the main
spindle 20 are stopped (step S2-2).
[0051] In step S2-2, if the displacement sensor 83 is of a contact
type, each servo motor 51a, 61a, 62a, 63a, 64a, 65a, 65b, 71a, 72a
is controlled such that a probe of the displacement sensor 83 is
arranged at a predetermined measurement position in contact with
the side surface of the tool holder 30. At this time, the servo
motors 71a, 72a are preferably controlled such that the center axis
of the probe and the normal line of the side surface of the tool
holder 30 substantially coincide with each other.
[0052] Next, the control unit 90 rotates the main spindle 20 by
controlling the rotation servo motor 22 (step S2-3), and causes the
memory device 91 to store detection values of the displacement
sensor 83 over a predetermined period of time in a state where the
main spindle 20 is rotated (step S2-4).
[0053] The detection values to be stored may be a series of
detection values that are continuously detected during the
predetermined period of time (a series of detection values changing
according to rotation of the main spindle 20), or may be detection
values at a plurality of points obtained, at predetermined
intervals, from a series of detection values detected during the
predetermined period of time. Also, in the case where the control
unit 90 is configured to receive data regarding a rotation position
of the main spindle 20, the series of detection values or the
detection values at a plurality of points may be stored in the
memory device 91 in association with rotation positions of the main
spindle 20.
[0054] Next, the control unit 90 determines the attached state of
the tool holder 30 based on the detection values obtained over the
predetermined period of time and stored in the memory device 91.
Specifically, for example, in the case where the difference between
the maximum value and the minimum value of the detection values
obtained over the predetermined period of time is smaller than a
predetermined reference value (step S2-5), the attached state is
determined to be normal (step S2-6), and in the case where the
difference between the maximum value and the minimum value of the
detection values obtained over the predetermined period of time is
equal to or greater than the predetermined reference value (step
S2-5), the attached state is determined to be abnormal (step S2-7),
and the display device 92 or the notification device 93 is
controlled to indicate that the attached state is abnormal (step
S2-8).
[0055] In this manner, in the second embodiment, when the side
surface of the tool holder 30 is displaced in a direction
orthogonal to the center axis of the main spindle 20 during
rotation of the main spindle 20, the detection value of the
displacement sensor 83 is changed according to the displacement.
Accordingly, if the position of the side surface of the tool holder
30 is deflected in a direction orthogonal to the center axis of the
main spindle 20, the runout is reflected in the detection values
obtained over the predetermined period of time. That is, the
attached state of the tool holder 30 may be determined based on the
detection values.
[0056] Moreover, the attached state of the tool 40 may be
determined in the same manner if the displacement sensor 83 is made
to come close to the side surface of the tool 40 in step S2-2.
[0057] A machining system according to a third embodiment of the
present invention will be described below with reference to the
drawings.
[0058] In contrast to the machining system of the first embodiment,
the machining system according to the present embodiment performs
detection by the force sensor unit 80 in a state where the main
spindle 20 is not rotated. Structures not described below are the
same as those in the first embodiment.
[0059] Operation of the control unit 90 at the time of
determination of the attached state of the tool holder 30 according
to the present embodiment will be described with reference to the
flowchart in FIG. 6.
[0060] When a condition for determination start is satisfied (step
S3-1) as in the first embodiment, the control unit 90 controls each
servo motor 51a, 61a, 62a, 63a, 64a, 65a, 65b, 71a, 72a such that
the probe 82 is arranged at a first measurement position in contact
with the side surface of the tool holder 30, as shown in FIG. 7, in
a state where the rotation servo motor 22 and the vertical movement
servo motor 23 of the main spindle 20 are stopped (step S3-2).
[0061] In this state, the control unit 90 causes the memory device
91 to store detection values received from the force sensor 81
(step S3-3).
[0062] Then, the control unit 90 controls each servo motor 51a,
61a, 62a, 63a, 64a, 65a, 65b, 71a, 72a such that the probe 82 is
arranged at a second measurement position in contact with the side
surface of the tool holder 30, as shown in FIG. 7 (step S3-4).
[0063] In this state, the control unit 90 causes the memory device
91 to store detection values received from the force sensor 81
(step S3-5).
[0064] Next, the control unit 90 controls each servo motor 51a,
61a, 62a, 63a, 64a, 65a, 65b, 71a, 72a such that the probe 82 is
arranged at a third measurement position in contact with the side
surface of the tool holder 30, as shown in FIG. 7 (step S3-6). The
servo motors 71a, 72a are preferably controlled such that the
center axis of the probe 82 and the normal line of the side surface
of the tool holder 30 substantially coincide with each other at the
first to the third measurement positions.
[0065] In this state, the control unit 90 causes the memory device
91 to store detection values received from the force sensor 81
(step S3-7).
[0066] Next, the control unit 90 determines the attached state of
the tool holder 30 based on the detection values for the first to
the third measurement positions stored in the memory device 91.
Specifically, for example, in the case where the difference between
the maximum value and the minimum value of the detection values for
each of the first to the third measurement positions is smaller
than a predetermined reference value (step S3-8), the attached
state is determined to be normal (step S3-9), and in the case where
the difference between the maximum value and the minimum value of
the detection values for each of the first to the third measurement
positions is equal to or greater than the predetermined reference
value (step S3-8), the attached state is determined to be abnormal
(step S3-10), and the display device 92 or the notification device
93 is controlled to indicate that the attached state is abnormal
(step S3-11).
[0067] In this manner, in the third embodiment, because the forces
with which the probe 82 comes into contact with first, second and
third circumferential positions of the tool holder 30 are detected
by the force sensor 81 in states where the probe 82 attached to the
distal end portion of the robot arm 60 is arranged at predetermined
measurement positions, if the side surface of the tool holder 30 is
shifted in a direction orthogonal to the center axis of the main
spindle 20, the detection values of the force sensor 81 change
according to the shift. Accordingly, if the position of the center
axis of the tool holder 30 is shifted in the direction orthogonal
to the center axis of the main spindle 20, the shift is reflected
in the detection values. That is, the attached state of the tool
holder 30 may be determined based on the detection values.
[0068] Moreover, the attached state of the tool 40 may be
determined in the same manner if the probe 82 is made to contact
the side surface of the tool 40 in steps S3-2, S3-4, S3-6.
[0069] Additionally, in the third embodiment, instead of performing
step S3-4, it is also possible to control each servo motor 51a,
61a, 62a, 63a, 64a, 65a, 65b, 71a, 72a such that the force sensor
81 and the probe 82 are arranged at the first measurement position
after the main spindle is rotated by the rotation servo motor 22 by
a predetermined angle (for example, 120 degrees) and is stopped,
and instead of performing step S3-6, it is also possible to control
each servo motor 51a, 61a, 62a, 63a, 64a, 65a, 65b, 71a, 72a such
that the force sensor 81 and the probe 82 are arranged at the first
measurement position after the main spindle 20 is further rotated
by the rotation servo motor 22 by a predetermined angle (for
example, 120 degrees) and is stopped.
[0070] Also in such a case, the probe 82 comes into contact with
the first, the second, and the third circumferential positions of
the tool holder 30, and the forces are detected by the force sensor
81, and thus, the attached state of the tool holder 30 may be
determined as in the case described above.
[0071] A machining system according to a fourth embodiment of the
present invention will be described below with reference to the
drawings.
[0072] In contrast to the machining system of the second
embodiment, the machining system according to the present
embodiment performs detection by the displacement sensor 83 in a
state where the main spindle 20 is not rotated. Structures not
described below are the same as those in the second embodiment.
[0073] Operation of the control unit 90 at the time of
determination of the attached state of the tool holder 30 according
to the present embodiment will be described with reference to the
flowchart in FIG. 8.
[0074] When a condition for determination start is satisfied (step
S4-1) as in the first embodiment, the control unit 90 controls each
servo motor 51a, 61a, 62a, 63a, 64a, 65a, 65b, 71a, 72a such that
the displacement sensor 83 is arranged at a first measurement
position near the side surface of the tool holder 30, as shown in
FIG. 9, in a state where the rotation servo motor 22 and the
vertical movement servo motor 23 of the main spindle 20 are stopped
(step S4-2).
[0075] In this state, the control unit 90 causes the memory device
91 to store detection values received from the displacement sensor
83 (step S4-3).
[0076] Then, the control unit 90 controls each servo motor 51a,
61a, 62a, 63a, 64a, 65a, 65b, 71a, 72a such that the displacement
sensor 83 is arranged at a second measurement position near the
side surface of the tool holder 30, as shown in FIG. 9 (step
S4-4).
[0077] In this state, the control unit 90 causes the memory device
91 to the store detection values received from the displacement
sensor 83 (step S4-5).
[0078] Then, the control unit 90 controls each servo motor 51a,
61a, 62a, 63a, 64a, 65a, 65b, 71a, 72a such that the displacement
sensor 83 is arranged at a third measurement position near the side
surface of the tool holder 30, as shown in FIG. 9 (step S4-6).
[0079] In this state, the control unit 90 causes the memory device
91 to store detection values received from the displacement sensor
83 (step S4-7).
[0080] Additionally, a case where the displacement sensor 83 is of
a non-contact type is described above, but in the case where the
displacement sensor 83 is of a contact type, the probe of the
displacement sensor 83 is made to contact the side surface of the
tool holder 30 at the first to the third measurement positions.
[0081] Next, the control unit 90 determines the attached state of
the tool holder 30 based on the detection values for the first to
the third measurement positions stored in the memory device 91.
Specifically, for example, in the case where the difference between
the maximum value and the minimum value of the detection values for
each of the first to the third measurement positions is smaller
than a predetermined reference value (step S4-8), the attached
state is determined to be normal (step S4-9), and in the case where
the difference between the maximum value and the minimum value of
the detection values for each of the first to the third measurement
positions is equal to or greater than the predetermined reference
value (step S4-8), the attached state is determined to be abnormal
(step S4-10), and the display device 92 or the notification device
93 is controlled to indicate that the attached state is abnormal
(step S4-11).
[0082] In this manner, in the fourth embodiment, because
displacement or a position is detected by the displacement sensor
83 attached to the distal end portion of the robot arm 60 for the
first, the second, and the third circumferential positions of the
side surface of the tool holder 30, if the side surface of the tool
holder 30 is shifted in a direction orthogonal to the center axis
of the main spindle 20, the detection values of the displacement
sensor 83 change according to the shift. Accordingly, if the
position of the center axis of the tool holder 30 is shifted in the
direction orthogonal to the center axis of the main spindle 20, the
shift is reflected in the detection values. That is, the attached
state of the tool holder 30 may be determined based on the
detection values.
[0083] Moreover, the attached state of the tool 40 may be
determined in the same manner if the probe 82 is made to come close
to the side surface of the tool 40 in steps S4-2, S4-4, and
S4-6.
[0084] Additionally, in the fourth embodiment, instead of
performing step S4-4, it is also possible to control each servo
motor 51a, 61a, 62a, 63a, 64a, 65a, 65b, 71a, 72a such that the
displacement sensor 83 is arranged at the first measurement
position after the main spindle is rotated by the rotation servo
motor 22 by a predetermined angle (for example, 120 degrees) and is
stopped, and instead of performing step S4-6, it is also possible
to control each servo motor 51a, 61a, 62a, 63a, 64a, 65a, 65b, 71a,
72a such that the displacement sensor 83 is arranged at the first
measurement position after the main spindle 20 is further rotated
by the rotation servo motor 22 by a predetermined angle (for
example, 120 degrees) and is stopped.
[0085] Also in such a case, the displacement sensor 83 comes close
to the first, the second, and the third circumferential positions
of the tool holder 30, and the position or displacement of the side
surface of the tool holder 30 is detected by the displacement
sensor 83, and thus, the attached state of the tool holder 30 may
be determined as in the case described above.
[0086] In the first to the fourth embodiments, the robot 50 and the
robot arm 60 are assumed to be for change of a workpiece, but the
robot 50 and the robot arm 60 may be for performing inspection of a
machined workpiece. For example, a sensor for inspection, such as a
camera, is attached to the distal end portion of the robot arm 60,
and the sensor is arranged at a predetermined position by the robot
arm 60, and inspection of a machined workpiece is thereby
performed.
[0087] Moreover, in the first to the fourth embodiments, the memory
device 91 may store, in the form of coordinate data or the like,
information about predetermined measurement positions in step S1-2,
step S2-2, step S3-2, step S3-4, step S3-6, step S4-2, step S4-4,
and step 4-6 so that each of a plurality of types of tools 40 may
be handled.
[0088] The control unit 90 may refer to the information, and may
control the robot arm 60 such that the probe 82 or the displacement
sensor 83 is arranged at a measurement position according to the
type of the tool 40 attached to the main spindle 20 in step S1-2,
step S2-2, step S3-2, step S3-4, step S3-6, step S4-2, step S4-4,
or step S4-6.
[0089] In this case, the probe 82 or the displacement sensor 83 is
arranged at an appropriate position according to the type of the
tool 40, and thus, there is an advantage when performing
determination of an attached state after the tool 40 is
replaced.
REFERENCE SIGNS LIST
[0090] 10 frame [0091] 11 workpiece holding section [0092] 20 main
spindle [0093] 30 tool holder [0094] 40 tool [0095] 50 robot [0096]
51 base [0097] 60 robot arm [0098] 61 base section [0099] 62
proximal arm [0100] 63 middle section [0101] 64 distal arm [0102]
65 chuck section [0103] 70 sensor support section [0104] 71 base
section [0105] 72 arm [0106] 80 force sensor unit [0107] 81 force
sensor [0108] 82 probe
* * * * *